This invention relates to a vortex valve having a variable inlet.
A vortex valve is disclosed in WO-A-99/43899. Such valves are used, for example in sewerage systems, for controlling fluid flow by a hydraulic effect without requiring moving parts. Such devices have a vortex chamber provided with an outlet at one axial end and an inlet arranged to cause swirl in the chamber when a certain critical flow has been attained. WO-A-99/43899 discloses a vortex valve in which the vortex chamber is defined by a circular cylindrical wall and two axial end walls.
At low flow rates, water entering through the inlet of a vortex valve passes through the vortex chamber to the outlet with substantially no pressure drop, and the valve can be considered to be open. At high flow rates, water enters through the inlet with enough energy to create a vortex in the vortex chamber which results in a significant pressure drop between the inlet and the outlet, which may greatly restrict flow through the outlet, or even substantially cut it off altogether. Thus the valve serves to limit the rate of flow automatically. Vortex valves can be used, for example, to control the flow of stormwater in sewers, to ensure that equipment downstream of the valve is not overloaded during periods of heavy rainfall.
Vortex valves are commonly installed in a collection chamber in which rain water, drained from road surfaces and other paved areas, collects. An outlet pipe extends from a wall of the collection chamber to a sewer, and the vortex valve is mounted so that its outlet makes a water-tight connection with the end of the outlet pipe. WO-A-99/43899 discloses mounting means for this purpose which comprises a first element fitted to the end wall of the vortex valve about its outlet opening, and a second element which is fitted to the outlet pipe. The vortex valve can then be fitted to the outlet pipe by connecting the two elements together.
The mounting means disclosed in WO-A-99/43899 requires the fitting of the second element to the outlet pipe. This is not always easy to achieve in a manner which will provide a water-tight connection between the vortex valve and the outlet pipe and is, in any case, a time consuming operation requiring fasteners and power tools.